The study of primate foods has moved from categorizing foods to documenting food material properties (FMPs) through the ecological insights of Warren Kinzey and technological breakthroughs of the Darvell-HKU tester. This shift has benefitted primatology by describing the toughness and to a lesser extent stiffness of many primate foods. As we advance our understanding of primate foods, we should expand beyond toughness to capture the multifaceted interactions between primates and their foods. In fact, recent arguments that FMPs show little relationship to primate skulls partly reflect this focus on toughness as just one of the many components of food texture.

Here, we look to Food Sciences, a discipline studying the composition and processing of human foods, as a model for future research into primate diets. Studies of primate FMPs have focused on linear-elastic fracture mechanics. Because many primate foods are viscoelastic, we can supplement these analyses by assessing how the rate of breakdown affects FMPs and their perception in primates. Moreover, studies of adhesiveness, cohesiveness and particle formation are warranted. Sensory analysis, although likely inferred for non-human primates, provides opportunities to understand how primates perceive food textural stimuli and flavor release. Finally, documenting how these material and sensory properties affect oral processing will be key to understanding the evolutionary interactions between primate feeding and diet. In summarizing these ideas, we advocate a texture hypothesis arguing that food textures and their perceptions change dynamically throughout a chewing sequence. Describing these interactions will be important for understanding the evolution of primate feeding.